This invention pertains to testing a body fluid for an analyte. More specifically, the present invention pertains to a novel needle design in combination with a collection apparatus for collecting a sample of such a fluid.
Numerous patents teach various ways for collecting a sample of body fluid and testing such fluid for an analyte such as glucose. For example, U.S. Pat. Nos. 5,820,570 and 5,823,973 describe methods and apparatus for obtaining, in one embodiment, interstitial fluid which is tested for glucose through IR absorption. These patents also describe use of the disclosed inventions in colormetric and electro-chemical testing of glucose.
Present development efforts are directed to testing very small volumes of body fluid (e.g. about 0.5 xcexcl). The use of such small volumes of fluid permits less painful collection of a fluid samples. However, small fluid volumes present additional challenges for analyte testing. For example, testing for analytes typically requires a fluid sample in excess of a predetermined minimum volume. By way of non-limiting representative example, a test may require a minimum sample size of about 1 to 5 xcexcl to yield reliable test results.
The ""973 patent shows a small diameter needle (about 28 to 32 gauge or about 0.36 mm to 0.23 mm outside diameter) with a length to penetrate into but not through a dermis to access interstitial fluid contained within the dermis. Preferably, the fluid is blood-free to facilitate subsequent testing of the fluid for analytes such as glucose.
The use of a small needle dimensioned as described in the ""973 patent greatly reduces pain. However, pain may occasionally occur. Further, there is a need for a needle design that enhances the rate at which a sample is collected by such a needle.
The present invention is directed to an apparatus for collecting a body fluid for testing for an analyte contained within said body fluid. The apparatus comprises a needle for penetrating a patient""s skin to access the fluid within said skin. The needle has a hollow body extending from a first end to a second end with a fluid pathway extending between the ends. The second end is positioned to deposit fluid for testing. The first end is configured to penetrate the skin and includes a beveled face on a front side of said body. The beveled face terminates at a penetration tip. The beveled face has an opening in communication with the fluid pathway. The body has a linear axis adjacent the first end. The first end includes a bend formed on the front side of the beveled face to be deflected toward said front side.